One very important aspect of the continuing evolution of silicon technology is the proliferation of microprocessors throughout our society. Because of the significant reductions in their size and cost, such processors can be economically used in many applications where the use of computers could not otherwise be justified. Even in applications where larger computers, e.g., minicomputers, have traditionally been used, the advantages of distributed processing have been obtained by using a number of microprocessors to perform the functions previously performed by a single larger processor. For example, many of the control functions previously performed by the central control unit in stored program controlled switching systems are being performed in more modern systems by a number of microprocessors which are distributed toward the system periphery and which communicate with each other to control system operation.
One countervailing factor to weigh against the established advantages of distributed processing is the large amount of power typically required to keep such distributed control processors continuously energized. This factor will become even more important as the cost of energy continues to increase. The power dissipation of microprocessors also becomes important when they are used in portable, battery-powered personal computers. In these applications and others, the ma9nitude of power required to operate microprocessor-based systems is a problem which diminishes the otherwise overall attractiveness of such systems.